**6. Frost resistance of Crimean native grape varieties and their hybrids**

Determination of frost-resistant native varieties of Crimea to identify sources of relative frost resistance and selection to the elite of the most frost-resistant genotypes obtained by crossing of native varieties of Crimea and hybrid varieties of complex interspecific origin is a promising direction of breeding work. The research objectives included: assessment of frost resistance of native varieties of Crimea by laboratory methods; selection to the elite the most frost-resistant genotypes obtained as a result of hybridization of Crimean native grape varieties with the complex interspecific hybrids.

As a result of the study, the frost resistance of 15 original forms, local varieties of Crimea, was tested using the laboratory method of assessment (**Figure 4**). The least frost resistance among the studied parental forms, local varieties of Crimea, showed the varieties 'Shabash', 'Soldaiya' and 'Solnechnodolinskii'. The best frost resistance to minus 24°C among the analyzed local varieties of Crimea was shown by the varieties 'Khersonesskii' and 'Kapselski'.

The results of our researches correspond to the results of assessment of the reaction of 84 Crimean native grape varieties of the ampelographic collection of the Magarach Institute on the influence of extreme winter temperatures of 2006 (−22.5 °C) obtained by the field method. An assessment of the preservation of the main and base buds, as well as the analysis of regenerative ability of the bushes, allows us to divide the studied varieties by frost resistance into three groups:

• the first group of non-resistant grape varieties; loss of 100% of main buds; loss of 95–100% of base buds; includes 57 varieties: 'Kandavasta', 'Kozskiy Stolovyi',' Nasurla', 'Shabash' and others; recovery of bushes of the remaining

**Figure 4.** *Differentiation of native grape varieties of the Crimea by resistance to frost.*

varieties was carried out with the help of base buds on fruit canes and sleeping buds of old wood of arms of the trunk and bush head;


All local varieties of Crimea belong to different ecological and geographical groups by their origin [5, 9]. Varieties 'Misgiuli Kara', 'Sary Pandas', 'Shabash' belong to the eastern ecological-geographical group - convar*. orientalis* Negr.; varieties 'Gevat Kara', 'Kokur Belyi', 'Misket', 'Tashly', 'Khersonesskii' belong to the ecological-geographical group of varieties of Black Sea Basin - convar*. pontica* Negr.; variety 'Kok Pandas' belongs to the west-european ecological-geographical group - convar. ossidentalis Negr. Separating the studied local varieties of Crimea into the groups of frost resistance, it should be noted that genotypes of convar. *pontica* Negr. and convar. ossidentalis Negr. possess high and average resistance to low temperatures, and varieties of the ecological-geographical group of convar*. orientalis* Negr. are classified as low frost-resistant and non-frost-resistant. In general, the data of resistance to low temperatures in various ecological-geographical groups correspond to the available literature sources.

During an agrobiological study in the period 2012–2015 the numbers of 21 elite forms were selected from 296 promising seedlings of the Crimean native varieties crossed with the complex interspecific hybrids. The yielded vine passed similar to the above method of laboratory freezing tests. It is established that the buds of eight elite seedlings hold reduction of temperature to minus 22°С (**Figure 5**).

After freezing through at minus 24°C hardwood cuttings of the following populations were capable to green shoots formation: 'Magarach No. 7-08-15-3', 'Magarach No. 11-08-17-2', 'Magarach No. 10-08-16-1', 'Magarach No. 10- 08-8-3', 'Magarach No. 11-08-15-2', 'Magarach No. 11-08-13-3', 'Magarach No. 10-08-14-2', 'Magarach No. 10-08-17-2', 'Magarach No. 4-08-17-3', 'Magarach No. 5-08-8-4', 'Magarach No. 4-08-3-3'.

Freezing through at temperature of minus 26 °C of hardwood cuttings of elite form 'Magarach No. 8-08-8-4' ('Kok Pandas' х 'Zeibel No. 6357') did not follow to the damage of buds, and gave normal shoots after the exit of dormant state. The forms selected to the elite in each population have different frost resistance. Such difference is observed in the population of 'Sary Pandas' x 'Tsitronnyi Magaracha' in the form 'Magarach No. 7-08-7-3': frost resistance is minus 22°C, and in the form 'Magarach No. 7-08-15-3' it reaches minus 24°C. Similar situation was revealed in the population 'Kefesiya' x 'Ifigenia', where the elite form 'Magarach No. 10-08-8-2' is characterized by frost resistance of minus 22°C, and 'Magarach No. 10-08-8- 3' - of minus 24°C. In the population 'Misket' x 'JS 26205', the form 'Magarach No. 4-08-17-4' withstands freezing through to minus 22°C, and the forms 'Magarach No. 4-08-17-3' and 'Magarach No. 5-08-8-4' - to minus 24°C. Moreover, almost all elite forms, in contrast to the initial Crimean native varieties in populations, are characterized by frost resistance higher by 2 °С.

*Biological Characteristics of Native Grape Cultivars of Crimean Region and Availability… DOI: http://dx.doi.org/10.5772/intechopen.98975*

**Figure 5.**

*Resistance to frost in hybrids of native varieties of Crimea.*
